And transparently map requests for grass7 provider to grass provider
It's misleading putting an old version number in the provider name,
when this provider supports grass versions 8 +
efficiently for many calls
Allows retrieval of some basic algorithm properties (display name,
icon) in an optimised way for many calls. (Avoiding multiple
expensive algorithmById lookups)
For the c++ api dox this expands to "\c nullptr" (the
\c directive indicates a code literal value), and for sipify/Python
it expands to ``None`` (`` is sphinx annotation for literal values)
Makes for nicer dox for both c++ and Python!
